This is the heavy-kerf 12 inch MK-500, and the .250 inch width is the reason to buy it rather than the standard .125. A quarter-inch kerf is what you want when the cut has to accept something afterwards: a backer rod and sealant in a control joint, a conduit run, a dowel, or a patch that needs a square shoulder to key into. It is also the more forgiving blade in a long straight cut, because a thicker core resists the wander and flex that a thin blade develops when a saw drifts.
Built for
- Sealant and expansion joint cuts that need a wide, square kerf
- Slab cuts where a conduit, dowel or repair key drops into the cut
- Long straight runs where a thin blade tends to wander
- Cured concrete slabs, sidewalks and curb work on 5 to 12 hp saws
- Repair cutouts where a clean shoulder matters more than cut speed
Specifications
- Model: MK Diamond MK-500, Standard grade for cured concrete
- Diameter: 12 inch (305 mm)
- Kerf (blade width): .250 inch
- Arbor: 1 inch
- Segment height: 10 mm
- Rim type: segmented, laser welded
- Cutting method: wet cutting only
- Published horsepower range for the MK-500 line: 5 to 12 hp
- MK Diamond part number: 128918
How to choose between grades
MK publishes its cured-concrete contractor blades in tiers that differ on segment height and the horsepower they are bonded for, not on cosmetics. The MK-500 standard grade carries a 10 mm segment and is rated 5 to 12 hp. The MK-505 premium grade carries a 12 mm segment and is rated 8 to 20 hp. Taller segment means more diamond to consume before the blade is spent, and the higher horsepower rating means the bond is built to survive the feed rate a bigger saw can push. Putting a premium blade on an underpowered saw will not make it cut faster, and putting a standard blade on a 20 hp saw will simply wear it out sooner. Match the blade to the saw first, then to the material.
Safe operation
This is a wet-cutting blade and it must be run with a continuous water feed. Running a wet blade dry is the single most common cause of segment loss, core warping and a scrapped blade, and it also puts respirable crystalline silica into the air. Water does two jobs at once: it carries heat out of the core and it knocks the dust down at the cut. Confirm your saw's arbor matches the blade before mounting, seat the blade flat against the flange, and never exceed the maximum operating speed stamped on the blade.
Frequently asked questions
Why would I pay for a .250 kerf instead of a .125?
Because of what goes into the cut afterwards. A quarter-inch kerf is sized for joint sealant, backer rod and repair keys. If you are only separating slab, the .125 costs less to run and cuts faster because it removes half the material.
Will a .250 blade cut slower?
Yes, and that is expected. A wider kerf removes twice the material per linear foot, so at the same horsepower your feed rate drops. Do not push it to compensate. Let the saw hold its speed.
Is my saw powerful enough?
MK publishes the MK-500 line for saws in the 5 to 12 hp range. A .250 kerf sits at the demanding end of that. If your saw is at the bottom of the range, expect a slower cut rather than a stalled one.
Wet or dry?
Wet only. Continuous water feed cools the core, clears slurry from a wide kerf where it can pack, and suppresses silica dust.
Discount Cleaning Products is an authorized MK Diamond dealer. We stock the contractor blade lines rather than drop-shipping whatever a marketplace listing happens to carry, so the part number you order is the part number MK prints in its own catalog. Our US-based team can confirm arbor size, kerf and horsepower fit against your saw before you buy, and can help you match bond hardness to the aggregate you are actually cutting.
